The dataset consists of grass biomass and green fractional cover measurements collected for 31 field plots in 2022 from Taita Taveta County, Kenya.The dataset further includes reflectance values (0–1) extracted for the field plots from multiple optical remote sensing data sources.These data were used in Vuorinne et al., Estimating grass biomass and fractional cover during a dry season in a Kenyan rangeland using multi- and hyperspectral remote sensing.For comprehensive details on data collection and processing, see the associated publication.